What Is Cloth-Covered Wiring and Is It a Fire Hazard?

What Is Cloth-Covered Wiring and Is It a Fire Hazard?

Cloth-covered wiring refers to electrical conductors insulated with rubber and wrapped in a braided fabric jacket — the standard wiring material used in Canadian homes from the early 1900s through the 1950s. The cloth is not the insulator; it is an outer protective braid over rubber insulation. The hazard is not the cloth itself — it is the rubber underneath, which degrades over decades and becomes brittle, cracked, and eventually crumbles away from the conductor.

Why It Becomes a Hazard

• The rubber insulation used in this era has a typical service life of 50–70 years. Homes still using original cloth-covered wiring are now 70–100 years past the installation date
• Once the rubber degrades, the conductor is bare or nearly bare. Bare conductors in contact with wood framing, insulation, or other conductors can arc and ignite
• Cloth-covered wiring has no ground conductor — it is a two-wire system. This means no equipment ground protection for connected devices and no support for modern GFCI or AFCI protection
• The cloth braid itself can accumulate dust, which is combustible in proximity to a heat source or arc
• Many Ontario insurers will not underwrite homes with active cloth-covered or knob-and-tube wiring, or they impose significant surcharges

What to Do

If your home has cloth-covered wiring, have it assessed by a licensed electrician before making assumptions about its condition. Wiring that appears intact from outside may have severely degraded rubber underneath. EZSMART inspects and replaces cloth-covered and knob-and-tube wiring across Ontario. Contact us to evaluate the scope and get a remediation quote.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp